(VAR )
(RULES
  f(a,b) -> c
  a -> a'
  b -> b'
  c -> f(a',b)
  c -> f(a,b')
  c -> f(a,b)
)
(COMMENT
doi:10.1007/3-540-61064-2_39
[10] Example 7
submitted by: Takahito Aoto, Junichi Yoshida, and Yoshihito Toyama
)